GtkScrolledWindow scrolling after change

Platform
1

I have a GtkScrolledWindow holding a GtkColumnView backed by a ListStore.

I have a button to add an entry to the bottom of the list (last entry). When I do this I want to programatically scroll the GtkScrolledWindow to the bottom (where the new row is). I’m using …

g_list_store_append ( listStore, calPoint );
GtkAdjustment *wScrollAdj = gtk_scrolled_window_get_vadjustment(  wScrolledWindow );
gtk_adjustment_set_value( wScrollAdj, gtk_adjustment_get_upper( wScrollAdj ) );

This doesn’t scroll to the bottom of the list but to the old bottom (before I added the row to the liststore).
Presumably the widgets have not had time to update to the expanded liststore. Can I trigger this before doing the scroll? How should this be handled?

Michael

Edit: I tried adding …

while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)
  g_main_context_iteration (NULL, TRUE);

after adding the item to the list but then it didn’t scroll at all … somehow it doesn’t even get to that line 8-(

2

Hi,

The ColumnView size is not immediately recomputed when inserting a new element. It’s done asynchronously.

You can schedule the scroll later in idle. In C that would look like this:

{
   ...
   g_list_store_append ( listStore, calPoint );
   GtkAdjustment *wScrollAdj = gtk_scrolled_window_get_vadjustment(  wScrolledWindow );
   g_idle_add_once (do_scroll, wScrollAdj);
}

void
do_scroll (gpointer user_data)
{
    GtkAdjustment *wScrollAdj = (GtkAdjustment *)user_data;
    gtk_adjustment_set_value( wScrollAdj, gtk_adjustment_get_upper( wScrollAdj ) );
}
1 Like
3

I considered that method but wasn’t going to suggest that because it was a bit ugly (and I was sure I’d be ridiculed :scream_cat:).

4

Maybe look at Gtk.GridView.scroll_to , it may work without the idle stuff, but I never tried…

5

This is for a GtkGridView … not a GtkScrolledWindow - would that work?

6

woops… I meant Gtk.ColumnView.scroll_to

7

Yes, I see there seems to be some inherent scroll capability in GtkColumnView but I couldn’t get this to work. The widget just kept growing without scrolling. This is why I put it in a scrolled window (which does work as expected).

8

ColumnView, like ListView, must be packed into a ScrolledWindow; the scroll_to() methods rely on that as well.

9

OK, then yes gtk_column_view_scroll does scroll the column view when inside a GtkScrolledWindow but it suffers from the same issue. I still need to have an idle process to do the scroll because the added item in the ListStore has not propagated through to the widget.

10

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